Description of the Related Art
Ibuprofen, the chemical name of which is 2-(4-isobutylphenyl)propionic acid, is a well known medicament with anti-inflammatory, antipyretic and analgesic activities. The uses of ibuprofen include the treatment of pain and inflammation in musculoskeletal disorders such as rheumatic disease, and the treatment of pain in a variety of other disorders, for example headache, neuralgia and dysmenorrhoea.
Ibuprofen and certain salts thereof, for example, the sodium salt, have a disagreeable taste. Accordingly, when tablets of ibuprofen are required for direct oral administration, they are generally coated, for example, with a sugar coating, so that the patient does not experience the disagreeable taste.
European patent application No. 94116 discloses therapeutic enteric-coated granules comprising (a) a non-steroidal, therapeutic active core, (b) a first coating adhered to said core containing a non-steroidal therapeutic active and a dispersing material, and (c) a second coating adhered to said first coating of an enteric material. The application discloses that the invention is applicable to numerous therapeutic actives, including ibuprofen. The dispersing material included in the first coating aids in the disrupting of the enteric coating in the intestines. It is disclosed that the dispersing material affects the pH of the environment and may be selected from a wide variety of materials, including aluminium hydroxide. The preferred dispersing materials are the alkali metal phosphate salts and glycine. This patent application does not disclose nor suggest that the disagreeable taste of ibuprofen or a salt thereof can be masked by the incorporation of aluminium hydroxide in a composition.
It is also known (see for example UK Patent Specifications Nos. 1,527,563, 2,003,028B and 2,079,600B) that aluminium salts of ibuprofen do not have a disagreeable taste and the use of aluminium salts of ibuprofen in a variety of pharmaceutical formulations has been proposed. However, it is desirable to find an excipient which may simply be added to compositions containing ibuprofen to overcome the undesirable taste, without involving the preparation of different salts of ibuprofen which may have a different or modified therapeutic activity from those pharmaceutically acceptable salts which are of recognized utility, or without involving complex formulation stages.